Typing rate control for type bar typewriters

ABSTRACT

A typing rate control for type bar typewriters to permit the realization of optimum overall typing rates wherein the code identification of a selected type bar, coded according to its position in a type basket, is held stored and is operative to call and cause the type bar it represents to print. The relative type bar position of the next to be called type bar and that of the type bar position in storage is ascertained by high speed counting logic circuitry and used to delay the call of the next type bar only over that time interval necessary to assure that the previously called type bar is out of the way.

United States Patent 1191 Niemietz 1 1 Jan. 30, 1973 541 TYPING RATE CONTROL FOR TYPE 2,995,231 8/1961 Von Kurnmer et al ..197/20 BAR IT R 3,068,985 12 1962 Arthur ....197 14 3,232,403 2/1966 Hebel ..1....l97/19 inventofl Jurgen Mamie", Nuemberg, 3,273,003 10/1966 OBrien etal. ...197/20 x Germany 3,289,806 12/1966 Manus ..197/19 l 3,291,277 12/1966 Borrelli et al ..197/20 [73] Assgnee' g g g Nuemberg 3,292,764 12/1966 Midgette et a1... ...197 20x many 3,340,987 9 19 7 Bastian ..197 20 [22] Filed: March 2,1970 3,414,104 12/1968 3,541,307 11/1970 Dirks ..197/20 X [21] Appl. No.: 15,373

Primary Examiner-Ernest T. Wright, Jr. [30] Foreign Application Priority Data A110 p Spalla March 13,1969 Germany l9 12 661.5 52 us. (:1. ..197/19, 340/1725, 197/17, A yp g rate control for yp bar typewriterS to p 197/14 mit the realization of optimum overall typing rates [51] Int. Cl. ..B4l j 5/30 wherein the code identification of a selected yp 58 Field of Search ....197/14, 17, 19, 20; 340 1725 coded a ing to its position in a yp basket, is held stored and is operative to call and cause the type [56] References Cited bar it represents to print. The relative type bar position of the next to be called type bar and that of the UNITED STATES PATENTS type bar position in storage is ascertained by high R26,954' 9/1970 Greene ..197/20 Speed counting logic circuitry d used to delay the 3,491,874 1/1970 Starck ..197/20 ux call of the next yp bar y over that time interval 3,301,371 1/1967 Lungwitz ..197/17 necessary to assure that the previously called type bar 2,512,860 6/1950 Heinrich .,l97/l9 X is out of the way. 2,848,090 8/1958 Sharpe et al.... ..197/19 2,865,487 12/1958 Hildebrandt ..197/20 9 Claims, 4 Drawing Figures PRINT SOLENOIDS TRANSLATOR DATA GATES .L.. DATA GATES SEPARATION COUNTER 44 :no-mzrugon EVALUATION LOGlC Tmux CONTROL LOGIC Tmin TYPING RATE CONTROL FOR TYPE BAR TYPEWRITERS BACKGROUND OF THE INVENTION Generally the writing machine that produces or prints out a hard copy is the slowest unit of a data handling system and imposes a limit on the speed at which data can be handled. In large data processing installations characterized by source units, e.g. computers, capable of delivering data at high rates of speed, the prior art has resorted to high speed parallel printout or line printers. In small data processing installations, however, it is not economical to employ such high speed parallel printout devices and the type bar typewriter, which is a serial character by character printer, because its high volume production allows it to be economically manufactured, is still the best answer.

Limitations on the rate at which type bars can be driven and consequently typing speeds attainable by type bar typewriters are imposed by dynamic, mechanical and design considerations. Overall typing speeds are limited also because a first called type bar must be out of the way before the next can be operated and the time required for one type bar to move out of the path of a subsequently to be operated type bar is related to the difference in positions from one another in the type segment. Thus the interval of delay required to allow typing of repeat characters is the longest, while the interval of delay required between any serial combination of two type bars spaced n or more positions apart in the type segment, is the shortest.

Stated otherwise, repeat characters represent a minimum typing rate and type bars spaced four or more positions apart a maximum typing rate.

In data processing applications where the typewriter is used as an output device, rather than limit the rate at which data can be handled to that at which repeat characters can be called, the prior art has proposed operating the system at a rate chosen to be somewhere above the minimum but still well below the maximum typing rates. Thus even though there are type bar combinations that can be operated at maximum typing rates, the maximum data handling'rate is limited to the chosen typing rate. In these machines provision is made, for example, to recognize repeat or adjacent characters and thereby to reduce the rate at which these characters are printed to the minimum rate. The patent to von Kummer et al. U.S. Pat. No. 2,995,231 is exemplary of such a compromise prior art solution.

Other proposals for increasing overall typing speed of type bar typewriters has been the provision of two identical sets of type bars from which type bars are called in turn. The patent to Arthur et al. U.S. Pat. No. 3,068,985 and the patent to Hebel U.S. Pat. No. 3,232,403 are exemplary of this approach. In the latter patent alpha characters are partially or altogether eliminated in order to accommodate two sets of numeric type bars.

All of these prior art proposals represent compromises and result in overall typing rates less than that which a type bar machine is capable of achieving. In the main they are restricted to alleviating the repeat or adjacent type bar limitations or require an investment in circuitry all out of proportion to the problem.

SUMMARY OF THE INVENTION The disadvantages of the known arrangements for serially calling type bars of an alpha numeric typing unit at optimum rates are overcome by the provision of timing and logic circuitry characterized by being simple, reliable and economical in its design which permits the realization of optimum overall typing speed by calling every possible combination of serially called type bars at their maximum rate.

In accordance with the invention, each type bar in a segment or type bar basket is assigned its position number in the segment, e.g. 1 through 44, and type bars are called to print by energization of solenoids, one after another, at intervals determined by the periods of monostable or one shot multivibrators comprising time delay means which are selectively triggered in accordance with the difference in segment positions of the last called type bar and the next to be called type bar. The difference in segment positions is determined by storing or placing in a counting register the code identification, by position, of a type bar last called or operated to print. The code identification of the next to be called type bar is entered and stored in a fixed register and the two stored positions are evaluated to determine the difference in the segment positions of two type bars whose code identifications are in the fixed and counting registers in a negligible time interval by high speed solid state counting, comparing, and related logic units. Depending on the difference in segment positions, one of the one shot multivibrators is triggered to delay the call of the next to be called type bar until an optimally calculated time, which is the period of the multivibrator, has elapsed. The one shot multivibrator with the longest time period is the one triggered when the next to be called type bar is the one last called, i.e., a repeat. This longest time period will be selected to be the optimum time for repeat character typing. The one shot multivibrator with the shortest time period is the one triggered when the next to be called type bar is positioned at least n type bars away from that last called. This then will be the max- 7 imum typing speed of the machine. One shot multivibrators with time periods intermediate the longest and shortest will be selectively triggered when the difference in segment positions of two type bars is less than n type bars and specially according to the difference. Thus the second of each two type bar combination will always be called to print at the optimum or fastest possible time after the first.

BRIEF DESCRIPTION OF THE DRAWING BRlEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, there is shown in FIG. 1 a dotted block designating a data source 11 which may be a record reader for sensing coded perforated or magnetic information carriers thereby to generate type bar representative combinations of binary digits on output or data lines 12 on receipt of a not-in-process signal on a command line 13. The number of output lines 12 will depend on the number of bits necessary to encode all of the type bars 14 in the segment of a typewriter. As shown in FIG. 2 the type bars 14 are encoded according to their position in the segment and are each provided with a print solenoid 15 for calling the type bars 14 to print. in a segment carrying forty-four type bars 14 a 6 bit code will be necessary and as shown in FIG. 2

' a straight binary notation is preferred with the leftmost type bar 14 assigned position number 1 and the type bar 14 at the extreme right position number 44.

Where the code representations of type bars 14 recorded on an information carrier being sensed or read is in a notation other than the preferred straight binary code notation assigning number representative codes to type bars 14 according to their positional location, the output of the reader designated 16 within block 11 may be sent over bit lines 17 to a code converter 18 to generate the adopted straight binary position code on lines 12.

The data source 11 alternatively, instead of a reader 16 and converter 18, may comprise a keyboard and encoder, wherein each key of the keyboard when depressed generates a signal on an associated one of a plurality of discrete lines which would in this alternative be connected to the inputs of an encoder, preferably straight binary as noted above, whereby the keyboard generated signals representing a character or type bar 14 is encoded according to the position of the type bar14 in the segment into a combination of signals on data lines 12. Data lines are hereinafter indicated in the drawing by double lines and discrete signal or control lines are shown as single lines.

The bit signals on data lines 12 from the source 11 are. stored in a fixed register 19 which initially is cleared by a reset signal on a line 21 from a control logic unit generally designated by reference 22. Preferably the fixed register 19 comprises flip flops, as many as there are bitsto define a character, which are set by l signals on associated data lines 12 and are simultaneously reset by a signal on line 21.

The fact of entry of data into the fixed register 19 is communicated to the control logic unit 22over register output lines 23 via an OR gate 24 and an AND gate 25, provided that the system control logic unit 22 is issuing a not-in-process signal to line 13 and to the AND gate 25 over line 26. When a signal passes AND gate 25 the system goes in-process and AND gate 25 is blocked.

The data output lines 23 of the 'fixed register 19 are also connected to associated normally closed data AND gates 27, and to a comparator 28 whose output line 29 is normally blocked by a forward or not-inreverse-count mode signal on line 31 from the control logic unit 22 for reasons hereinafter apparent.

Assuming that the data in the fixed register 19 is the first data entered, a counting register 32, which serves, as will hereinafter appear, to store the previously entered type bar position signals, will be in a zero condition with no 1 signals on any of its output lines 33. The counting register output lines 33 are coupled to normally closed data AND gates 34, to the comparator 28, and to an OR gate 35.

The output from the OR gate 35 and AND gate 25 under these conditions, i.e. a zero count in the counting register 32, position data in the fixed register 19, and the absence of pulses from a pulse generator 36 will, as will hereinafter be clear, be operative by way of the control logic unit 22 to cause the triggering of a 0 one shot multivibrator 46 whose output pulse leading and trailing edges respectively, will control logic the issuance from the control unit 22 over line 37 of a gating signal to AND gates 27 of sufficient duration, whereby data n the fixed register 19 will be transferred to the counting register 32 over data lines 38 and, a short time later, to generate a second gate signal on line 39 of sufficient duration thereby to pass via AND gates 34 the code now in the counting register 32 to a six level trAnslator (decoder) 40 to energize a selected one of the print solenoids 15 which will call the type bar 14 in the printer.

The control logic unit 22 will also, following a'short delay after generating a gate signal on line 39, generate a fixed register clear signal on line 21 and a not-inprocess signal to lines 13 and 26 telling source 11 to issue the next to be called type bar code signals. If the source 11 is a keyboard, the signal may unlock the keyboard or light a light indicating that another key may be depressed. If the source 11 is a reader 16 the not-in-process signal will command-the reader 16 to issue the next to be called type bar position code.

When data is in both registers 19 and 32 the output of OR gate 35 and that from AND gate 25 will cause the control logic unit 22 to issue a signal over a line 36' to start the pulse generator 36 which operates at very high frequency. The pulse generator 36 is connected to deliver pulses over line 41 to the counting register 32 and to a separation counter 42 capable, for reasons hereinafter evident, of counting to a number equal to twice that minimum number of positions, n, a second type bar 14 to be typed can be from a first called bar 14 as will allow the second to be called at the maximum typing rate.- It has been found for example, that if two type bars 14 are separated by three other type bars 14,

i.e., are four positions apart, the second type bar 14 located to either side of the first, then typing can proceed at the maximum rate. Type bars 14 more than n=4 positions apart may also proceed at the maximum rate. Thus with n=4 the separation counter 42 will be designed to count to eight, i.e. 0-7. Both the counting register 32 and the separation counter 42 are of the type capable of counting in a forward and backward or reverse direction when so conditioned by signals applied thereto over line 43 from the control logic unit 22. The count in separation counter 42 is coupled over lines 44 carrying signals representing the count of separation counter 42 at particular times to an evaluation logic unit 45 in the form of logical AND and OR gates which will evaluate and pass the signals on lines 44 and trigger an appropriate one of one shot multivibrators 46 comprising time delay means.

In accordance with the invention the count in the separation counter 42 at the time of coincidence indicating identity of all bits in the fixed and counting registers 19 and 32 is a measure of the difference n, n-l n-2 l, in the segment positions of a first called type bar 14 that is stored in counting register 32 at the start of the cycle, and the next to be called type bar 14 that was entered into fixed register 19. As will be explained hereinafter assuming n=4, if the count is four at coincidence, it means no difference in segment position of the two called type bars 14, i.e., a repeat character, and the 4 count signal on associated output line 44 will trigger the 4 one shot multivibrator 46 which has the longest period. A count of 3 or 5 on associated output line 44 at coincidence means the second type bar 14 to be typed is one segment position from the first type bar 14 called or an adjacent (either side of the first) type bar 14, a count of 2 or 6 on associated output line 44 at coincidence means the second the second type bar 14 to be typed is two segment positions from the first type bar 14 called or is separated therefrom by one other type bar 14, a count of 1 or 7 at coincidence means the second type bar 14 to be typed is three segment positions from the first called type bar 14 or is separated therefrom by two other type bars 14, and a count of zero at coincidence means the second type bar 14 to be typed is four segment positions from the first called type bar 14 or is separated therefrom by other type bars 14. Thus in the drawing five one shot multivibrators 46 are shown with the 0 one shot multivibrator 46 having the shortest, r and the 4 one shot multivibrator 46 having the longest, T,,,,,,,, period.

Whenever a code in the fixed register 19 represents a type bar 14 more than four, where n=4, positions from that of the type bar 14 represented by the code in the counting register 32, the separation counter 42 will go to zero before coincidence can occur and the signal representing zero on line 44 in this event, as will become clear, will be operative in the evaluation logic unit 45 to effect the call of the shortest period or 0 one shot multivibrator 46.

In view of the above, it is necessary to ascertain whether a second type bar 14 is within four positions, to either side, of the position of a first type bar 14. Thus the separation counter 42 must be capable of counting eight pulses. To count eight pulses, a three stage separation counter 42, counting from 0-7, is necessary. The separation counter 42 is preset to a count of4 over a line 47 from the control logic unit 22. Also the control logic unit 22 initiallY instructs over line 43 the counting register 32 and the separation counter 42 to count in the forward direction. During the forward count mode, the output line 29 of comparator 28, as hereinbefore noted, is blocked by a signal on line 31.

Thus when the pulse generator 36 starts in response to the presence of data bits in both registers 19 and 32, the counts in counting register 32 and separation counter 42 increase until the count in separation counter 42 goes to zero (after four pulses) so that during a subsequent backward count, eight positions, four positions to either side of the position in counting register 32 at the start, will be looked at by the evaluation logic unit 45.

When separation counter 42 reaches zero during the forward count the zero count signal on the output line 44 of counter 42 in logic combination with the forward count mode signal on line 49 generates a signal on a line 48 which acts in the control logic unit 22 to cause it to issue a backward count mode signal over line 43, to issue a signal over line 31 to unblock the comparator output line 29, and to issue a not-in-forward count signal on line 49 to the evaluation logic unit 45. It is here noted that because a forward count mode signal is on line 49, a zero signal on line 44 during forward count is not effective to trigger the 0 one shot multivibrator 46.

If there is coincidence of code bits in registers 19 and 32 at the time the control logic unit 22 shifts to backward count mode, the 0 count signal on associated line 44 will be gated through evaluation logic unit 45 to trigger 0 one shot multivibrator 46. Otherwise, if during the backward count, but before counter 42 again goes to zero on the eighth pulse, coincidence of the code bits in registers 19 and 32 occurs, a signal on comparator output line 29 will cause the evaluation logic unit 45, if the count is l or 7, 2 or 6, 3 or 5, or 4 to pass a signal over associated lines 45 to trigger the associated one of the other four one shot multivibrators 46 1, 2, 3 or 4 respectively.

If there is no coincidence signal during the backward count to zero, indicating the two type bar positions in storage are greater than n or four positions apart, the evaluation logic unit 45 will act on the zero count signal on associated output line 44 and the backward count mode signal on line 49 to trigger the 0 or fastest one shot multivibrator 46 i.e., the one with the shortest period as hereinabove noted.

When, as hereinbefore noted, the counting register 32 is zero at the time data is entered into the fixed register 19, it communicates this fact through OR gate 35 to the control logic unit 22 which will issue to the evaluation logic unit 45 over lines 51 and 52 respectively the fact that the counting register 32 is zero and pulse generator 36 is not generating pulses, thereby to cause the 0. one shot multivibrator 46 to be triggered.

The outputs of the one shot multivibrators 46 are coupled over lines 46 to the control logic unit 22 wherein the leading edges of their output pulses generate signals operative to turn off the pulse generator 36, stopping the generation of pulses, to clear the counting register 32 over line 53, to issue a forward count mode signal to lines 43 and 49, to issue a comparator output blocking signal to line 31, and to reset the separation counter 42 to its original preset condition, a count of 4.

With counting register 32 cleared in response to the leading edge of the output or timing pulse of a multivibrator 46, or having been initially cleared and responsible, as hereinbefore noted, for causing the generation of the 0" multivibrator timing pulse, the control logic unit 22 acts in response to the leading edge thereof also to issue a gate signal over line 37 whereby the data in the fixed register 19 will be passed through gates 27 and transferred in parallel over data lines 38 to the counting register 32. The control logic unit 22 also acts in response to the trailing edge of the timing pulse from the selected one shot multivibrator 46 to issue a gate signal to line 39, thereby to pass the data now on counting register output lines 33 through gates 34 to the translator 40 to operate a selected print solenoid 15, and also to issue a signal on line 21 to clear the fixed register 19. Following the pulse trailing edge,

and after a delay shorter than the period of the fastest one shot multivibrator 46, the control logic unit 22 will issue a not-in-process signal to lines 13 and 26 thereby to allow the source 11 to issue another type bar position code and to condition AND gate 25 to start another process cycle on entry of data into fixed register 19.

An example will illustrate the operation of the circuit. If it is assumed that n=4 and that the last called character was the type bar 14 in the number 12 position from the left end type bar 14 in the basket i.e., the 4 type bar 14 (FIG. 2) then the counting register 32 will contain the binary equivalent of number 12, the counter 42 will be set to its basic setting, four, as noted hereinbefore, a comparator blocking signal will be on line 31 and a forward count mode signal will be on lines 43 and 49. If now the code issued and representing the type bar 14 next to be called is, for example, the f type bar 14 at position 15 (FIG. 2), and is entered into the fixed register 19, the signals at the output of AND gate 25 and OR gate 35 will cause the control logic unit 22 to start a process cycle by turning on the pulse generator 36. As noted above the count will be forward until the count in separation counter 42 increases from 4 to zero. At the same time, the count in counting register 32 will have gone forward from 12 to 16 and have the binary representation of the count of 16 therein. As hereinbefore noted, during forward counting the comparator output line 29 is blocked. However when separation counter 42 zero the signal on its zero (0) output line 44 via line 48 emanating from evaluation logic unit 45 will cause the control logic unit 22 to issue a backward count mode signal to lines 31, 43 and 49 and backward counting will commence. Also output line 29 of the comparator 28 will be unblocked and the evaluation logic unit 45 will be conditioned. The count in counting register 32 and separation counter 42 will now proceed backward until, one pulse later, counting register 32 gets back to a count of 15 which is then coincident with fixed register 19. The coincidence signal on comparator output line 29 will cause the count in separation counter 42 to be evaluated, i.e., it will cause a signal on the output line 44 of the counter 42 representing the count at the time of coincidence to pass through an evaluation logic unit 45 and trigger its associated one shot multivibrator 46. More particularly as the backward count started with separation counter 42 at zero and coincidence was reached one pulse later, separation counter 42 will have a count of 7 which fact is signaled as noted infra via AND gates within the evaluation logic unit 45 to the 1" one shot multivibrator 46 to generate a pulse whose period was chosen to allow the type bar l4 at position 15 to be called at the soonest possible time after the type bar 14 at position 12 was called.

With reference to FIG. 3, the evaluation logic unit 45 hereinbefore described functionally, is shown to include therein AND gates 54, 55, 56, 57 and 58 each of which have one input connected to an associated line 44 and are adapted to pass a count signal on the associated one of the output lines 44 from the separation counter 42 if the backward (BKWD) or reverse count mode signal is present on line 49 and acoincidence signal is present on line 29; lines 29 and 49 being also connected to all of the other inputs of AND gates 54-58. Also included is an AND gate 59 adapted to pass the signal on zero count line 44, if there is not a coincidence (COINC) signal present on line 29 connected to the second of its inputs, and a backward count mode signal is present on line 49 connected to its third input. An AND gate 60 is also provided to pass a signal to line 48 to switch a forward-reverse flip-flop 64 in control logic unit 22 to a backward count mode, if the count from separation counter 42 reaches zero, indicated by a signal on the 0 count line 44 that is connected to one of its inputs, and there is a forward count mode signal present on line 49 connected to its other input. The evaluation logic unit 45 further includes an AND gate 61 adapted to pass a signal to energize the 0 line 45' to the 0" one-shot multivibrator 46 when lines 51 and 52 to its input carry signals indicating the fixed register 19 is not zero and counting register 32 is zero, and the pulse generator 36 is off. The output of AND gates 58, 59 and 61 pass through OR gate 62 to line 45' leading to the 0" one-Shot multivibrator 46.

With reference to FIG. 4, the control logic unit 22 hereinbefore described logically functionally is shown to include a pulse generator control flip-flop 63, a forward-backward count mode control flip-flop 64 and a system in-process flip-flop 65. As noted hereinbefore, if there is not data in the counting register 32, and information is entered into the fixed register 19, indicated by the output signal condition of OR gate 35 and AND gate 25 respectively whose output lines are connected to an AND gate 66, a signal will pass AND gate 66 to line 51. Entry of data into the fixed register 19 will also set the process flip-flop 65 to an in-process condition whose output line 13 will inhibit the data source 11. Also as described, if data is in the counting register 32 when data enters fixed register 19, indicated by the output signal condition of OR gate 35 and AND gate 25 respectively, whose output lines are also connected to an AND gate 67, a signal will pass the AND gate 67 and set the pulse generator control flip-flop 63, turning on the pulse generator 36 over line 36'. Line 52 is shown connected to the output of pulse generator control flipflop 63, which in reset state, signals over line 52.to AND gate 61 in the evaluation logic unit 45 that the pulse generator 36 is off.

As previously described, a signal on line 48 from unit 45 will reset the forward-reverse flip-flop 64 to backward count mode (BKWD). Lines 31, 43 and 49 connected to its output thereby condition, respectively, the comparator 28 whereby the data in fixed register 19 can be compared with that in counting register 32, the counting register 32 and the separation counter 42 for backward counting, AND gates 54-59 to pass count signals on their respective count lines 44 during backward count mode, and AND gate 60 in the evaluation logic unit 45 to pass a 0 count signal on line 44 during forward count mode. Also as described, signals on lines 45' from the evaluation logic unit 45 will trigger associated one shot multivibrators 46. The output pulses of the one shot multivibrators 46 are passed via output lines 46' thereof through an OR gate 68 in the control logic unit 22 to a circuit 69, e.g., a differentiating circuit, which will generate signals in response to the leading and trailing edges of pulses issuing from OR gate 68. The output signal from circuit 69 resulting from the leading edge of the pulse from OR gate 68 is carried via a line 71 to reset or turn off the pulse generator control flip-flop 63 thereby to stop the pulse generator 36, is connected to line 47 to presetthe separation counter 42, is connected to line 53 to clear the counting register 32 so that data from fixed register 19 can be transferred thereto, is connected to trigger a delay circuit shown as a one-shot multivibrator 73 thereby to energize line 37 over the on-time period of the one-shot multivibrator 73 thereby to transfer the data in the fixed register 19 to the now cleared counting register 32, and is also connected to set the forward-backward count mode flip-flop 64 to forward count mode which mode signal is also carried on lines 31, 43 and 49.

The output signal from circuit 69 resulting from the trailing edge of the output pulse from OR gate 68 is carried via a line 72 to trigger a one-shot multivibrator 74 thereby to energize line 39 over its one-time interval to effect gating of data from the counting register 32 through AND gates 34 to print solenoids 15, is connected to line 21 to effect the resetting of the fixed register 19 and, after a delay provided by a delay circuit 75, to permit resetting of fixed register 19, to reset the process flip-flop 65 to enable entry of further data issued from source 11 into the now cleared fixed register 19. Data issues from the data source in response to the not in-process signal on line 13.

In one type bar typewriter capable of operating at a maximum 20 per second rate the timing control described was used to call the same type bar a second time, which requires the longest delay, at an effective typing rate of 10 characters per second; neighboring type bars, alternately selected, at a 12 character per second rate; type bars separated by one type bar alternately at a 16 character per second rate; type bars separated by two type bars alternately at an 18 character per second rate, and type bars separated by three or more type bars alternately at the 20 character per second maximum rate.

It is to be understood that the separator counter 42 might also have been zerod in a backward mode and looked at for the difference in segment positions in the forward mode.

The invention claimed is:

l. The combination with a typewriter having individual type bars supported in a side by side array in a type bar segment and assigned numbers in ascending order from one end to the other end of said array and provided with print solenoids responsive to coded signals representing said type bars according to the number assigned to their segment position in said array for actuating said type bars, of source means for issuing type bar representative coded signals, and circuitry for controlling the energization of said print solenoids in response to coded signals issuing one after another as soon as possible depending on the relative segment position of any two type bars to be actuated in sequence, said circuitry comprising,

fixed register means for storing coded signals issued by said source means representing a next to be typed type bar,

counting register means for storing the coded signals representing the last type bar whose print solenoid was energized,

means responsive to entry of coded signals into said fixed register means for generating discrete signals representing the difference in segment position of said type bars whose representative coded signals are in said fixed and counting register means comprising,

means for generating pulses,

means applying said pulses to said counting register means,

means for comparing the coded signals in said fixed register means and coded signals in said counting register means for coincidence,

means for counting said pulses from the time of entry of signals into said fixed register means to the time of coincidence of coded signals in said fixed and counting register means,

and means for generating a discrete signal corresponding to the count at coincidence of coded signals in said fixed and counting register means,

time delay means responsive to said discrete signals for generating output signals for clearing said counting register means and whose duration establishes the interval of delay necessary after energization of the last print solenoid as will allow energization of the print solenoid associated with the type bar whose coded signals were entered into said fixed register means at the soonest possible time,

and gating means controlled by said output signals for transferring coded signals from said fixed to said cleared counting register means and for energizing the print solenoid associated with the type bar represented by the coded signals transferred to said counting register means.

2. The combination recited in claim 1 further comprising means for instructing said source means to issue coded signals of the next succeeding type bar to be actuated. v

3. The combination recited in claim 1 wherein said gating means includes first and second gate means,

means operable in response to the leading edge of the output pulse of a selected one shot multivibra tor to clear said counting register means, and to open said first gate means to transfer the coded signals-in said fixed register means to said counting register means,

and means responsive to the trailing edge of said selected one shot multivibrator output pulse to open said second gate means to pass coded signals transferred to said counting register means to a translator to energize a selected print solenoid.

4. The combination with a typewriter having individual type bars supported in a side by side array in a type bar segment and assigned numbers in ascending order from one end to the other end of said array and provided with print solenoids responsive to coded signals representing said type bars according to the number assigned to their segment position in said array for actuating said type bars, of source means for issuing type bar representative coded signals, and circuitry for controlling the energization of said print solenoids in response to coded signals issuing one after another as soon as possible depending on the relative segment position of any two type bars to be actuated in sequence, said circuitry comprising,

a fixed register for storing coded signals issued by said source means representing next to be actuated type bars,

a counting register for storing the coded signals of the last type bar whose solenoid was energized,

a separation counter capable of counting to Zn and preset to a count of n where n represents the minimum difference in segment position permitting the next to be actuated type bar to be called at the maximum rate,

means responsive to entry of signals into said fixed register for generating pulses and applying said pulses to said counting register and said separation counter,

means for reversing the direction of counting in said counting register and separation counter after n pulses,

means for comparing coded signals stored in said registers for coincidence after reversal of the direction of counting,

means for evaluating the count in said separation counter if coincidence of coded signals stored in said registers occurs within 2n pulses and generating a corresponding discrete count signal,

time delay means responsive to said discrete count signals to effect the transfer of coded signals -in said fixed register to said counting register and for passing the coded signals in said counting register to energize the print solenoid of the next to be called type bar at the soonest possible time following energization of the print solenoid of the last called type bar,

and means for operating the time delay means allowing the print solenoid of the next to be actuated type bar to be energized in the shortest interval following energization of the print solenoid of the last called type bar whenever coincidence does not occur within 2n pulses.

5. The combination recited in claim 4 wherein said time delay means includes a plurality of one shot multivibrators with each corresponding to one of the differences in segment position n, nl, n2 l, of any two type bars, the period of the multivibrator output pulses representing the delay interval necessary between any. two type bar combination according to the difference in their segment position,

gate means responsive to the leading edge of said output pulse for transferring the coded signals in said fixed to said counting registers, and to the trailing edge of said output pulse for gating said coded signals in said counting register to effect the energization of a print solenoid.

6. The combination recited in claim 5 further including means for instructing said source means to issue other coded signals following a predetermined delay after the said trailing edge of said output pulses.

7. The combination recited in claim 5, including means for triggering the n one shot multivibrator if coincidence of coded signals in said registers has not occurred before a return to zero of said separation counter following reversal in the direction of counting.

8. The combination with a typewriter having individual type bars supported in a side by side array in a type bar segment and assigned numbers in ascending order from one end to the other end of said array and provided with print solenoids responsive to coded signals representing said type bars according to the number assigned to their segment position in said array for actuating said type bars, of source means for issuing type bar representative coded signals, and circuitry for controlling the energization of said print solenoids in response to coded signals issuing one after another as soon as possible, said circuitry comprising,

fixed register means for storing coded signals issued by said source means representing a next to be typed type bar,

counting register for storing the coded signals representing the last type bar whose print solenoid was energized,

a plurality of one shot multivibrators whose output pulse periods correspond to the delay necessary before actuating the second of two type bars spaced n, nl, n2-1, 0 segment positions apart, when n is the minimum difference in segment position permitting the fastest sequential actuation of any two type bars,

means responsive to entry of coded signals into said fixed register means for generating discrete signals representing the difference in segment position of the last and next to be actuated type bars whose coded signals are in said fixed and counting register means including,

a pulse generator operable on entry of signals into said fixed register means to pulse said counting register,

means comparing the coded signals in said fixed register means and the coded signals in said counting register for coincidence and for generating a coincidence signal,

means for counting to Zn in response to pulses from said pulse generator, and

means for generating discrete signals corresponding to the count in said counting means if coincidence occurs within 2n counts,

means for passing said discrete signals to trigger corresponding one shot multivibrators for generating output signals whose duration establishes the interval of delay necessary after energization of the last print solenoid as will allow energization of the print solenoid associated with the type bar whose coded signals were entered into said fixed register means-in the soonest possible time,

and gating means controlled by output signals generated for clearing said counting register, for transferring coded signals from said fixed to said counting register and for energizing the print solenoid associated with the type bar represented by the coded signals transferred to said counting register.

9. The combination recited in claim 8 further including means for triggering the one shot multivibrator responding to a difference in segment positions equal to n when the number of pulses generated exceeds 2n. 

1. The combination with a typewriter having individual type bars supported in a side by side array in a type bar segment and assigned numbers in ascending order from one end to the other end of said array and provided with print solenoids responsive to coded signals representing said type bars according to the number assigned to their segment position in said array for actuating said type bars, of source means for issuing type bar representative coded signals, and circuitry for controlling the energization of said prInt solenoids in response to coded signals issuing one after another as soon as possible depending on the relative segment position of any two type bars to be actuated in sequence, said circuitry comprising, fixed register means for storing coded signals issued by said source means representing a next to be typed type bar, counting register means for storing the coded signals representing the last type bar whose print solenoid was energized, means responsive to entry of coded signals into said fixed register means for generating discrete signals representing the difference in segment position of said type bars whose representative coded signals are in said fixed and counting register means comprising, means for generating pulses, means applying said pulses to said counting register means, means for comparing the coded signals in said fixed register means and coded signals in said counting register means for coincidence, means for counting said pulses from the time of entry of signals into said fixed register means to the time of coincidence of coded signals in said fixed and counting register means, and means for generating a discrete signal corresponding to the count at coincidence of coded signals in said fixed and counting register means, time delay means responsive to said discrete signals for generating output signals for clearing said counting register means and whose duration establishes the interval of delay necessary after energization of the last print solenoid as will allow energization of the print solenoid associated with the type bar whose coded signals were entered into said fixed register means at the soonest possible time, and gating means controlled by said output signals for transferring coded signals from said fixed to said cleared counting register means and for energizing the print solenoid associated with the type bar represented by the coded signals transferred to said counting register means.
 1. The combination with a typewriter having individual type bars supported in a side by side array in a type bar segment and assigned numbers in ascending order from one end to the other end of said array and provided with print solenoids responsive to coded signals representing said type bars according to the number assigned to their segment position in said array for actuating said type bars, of source means for issuing type bar representative coded signals, and circuitry for controlling the energization of said prInt solenoids in response to coded signals issuing one after another as soon as possible depending on the relative segment position of any two type bars to be actuated in sequence, said circuitry comprising, fixed register means for storing coded signals issued by said source means representing a next to be typed type bar, counting register means for storing the coded signals representing the last type bar whose print solenoid was energized, means responsive to entry of coded signals into said fixed register means for generating discrete signals representing the difference in segment position of said type bars whose representative coded signals are in said fixed and counting register means comprising, means for generating pulses, means applying said pulses to said counting register means, means for comparing the coded signals in said fixed register means and coded signals in said counting register means for coincidence, means for counting said pulses from the time of entry of signals into said fixed register means to the time of coincidence of coded signals in said fixed and counting register means, and means for generating a discrete signal corresponding to the count at coincidence of coded signals in said fixed and counting register means, time delay means responsive to said discrete signals for generating output signals for clearing said counting register means and whose duration establishes the interval of delay necessary after energization of the last print solenoid as will allow energization of the print solenoid associated with the type bar whose coded signals were entered into said fixed register means at the soonest possible time, and gating means controlled by said output signals for transferring coded signals from said fixed to said cleared counting register means and for energizing the print solenoid associated with the type bar represented by the coded signals transferred to said counting register means.
 2. The combination recited in claim 1 further comprising means for instructing said source means to issue coded signals of the next succeeding type bar to be actuated.
 3. The combination recited in claim 1 wherein said gating means includes first and second gate means, means operable in response to the leading edge of the output pulse of a selected one shot multivibrator to clear said counting register means, and to open said first gate means to transfer the coded signals in said fixed register means to said counting register means, and means responsive to the trailing edge of said selected one shot multivibrator output pulse to open said second gate means to pass coded signals transferred to said counting register means to a translator to energize a selected print solenoid.
 4. The combination with a typewriter having individual type bars supported in a side by side array in a type bar segment and assigned numbers in ascending order from one end to the other end of said array and provided with print solenoids responsive to coded signals representing said type bars according to the number assigned to their segment position in said array for actuating said type bars, of source means for issuing type bar representative coded signals, and circuitry for controlling the energization of said print solenoids in response to coded signals issuing one after another as soon as possible depending on the relative segment position of any two type bars to be actuated in sequence, said circuitry comprising, a fixed register for storing coded signals issued by said source means representing next to be actuated type bars, a counting register for storing the coded signals of the last type bar whose solenoid was energized, a separation counter capable of counting to 2n and preset to a count of n where n represents the minimum difference in segment position permitting the next to be actuated type bar to be called at the maximum rate, means responsive to entry of signals into Said fixed register for generating pulses and applying said pulses to said counting register and said separation counter, means for reversing the direction of counting in said counting register and separation counter after n pulses, means for comparing coded signals stored in said registers for coincidence after reversal of the direction of counting, means for evaluating the count in said separation counter if coincidence of coded signals stored in said registers occurs within 2n pulses and generating a corresponding discrete count signal, time delay means responsive to said discrete count signals to effect the transfer of coded signals in said fixed register to said counting register and for passing the coded signals in said counting register to energize the print solenoid of the next to be called type bar at the soonest possible time following energization of the print solenoid of the last called type bar, and means for operating the time delay means allowing the print solenoid of the next to be actuated type bar to be energized in the shortest interval following energization of the print solenoid of the last called type bar whenever coincidence does not occur within 2n pulses.
 5. The combination recited in claim 4 wherein said time delay means includes a plurality of one shot multivibrators with each corresponding to one of the differences in segment position n, n-1, n-2 - - - 1, 0 of any two type bars, the period of the multivibrator output pulses representing the delay interval necessary between any two type bar combination according to the difference in their segment position, gate means responsive to the leading edge of said output pulse for transferring the coded signals in said fixed to said counting registers, and to the trailing edge of said output pulse for gating said coded signals in said counting register to effect the energization of a print solenoid.
 6. The combination recited in claim 5 further including means for instructing said source means to issue other coded signals following a predetermined delay after the said trailing edge of said output pulses.
 7. The combination recited in claim 5, including means for triggering the n one shot multivibrator if coincidence of coded signals in said registers has not occurred before a return to zero of said separation counter following reversal in the direction of counting.
 8. The combination with a typewriter having individual type bars supported in a side by side array in a type bar segment and assigned numbers in ascending order from one end to the other end of said array and provided with print solenoids responsive to coded signals representing said type bars according to the number assigned to their segment position in said array for actuating said type bars, of source means for issuing type bar representative coded signals, and circuitry for controlling the energization of said print solenoids in response to coded signals issuing one after another as soon as possible, said circuitry comprising, fixed register means for storing coded signals issued by said source means representing a next to be typed type bar, a counting register for storing the coded signals representing the last type bar whose print solenoid was energized, a plurality of one shot multivibrators whose output pulse periods correspond to the delay necessary before actuating the second of two type bars spaced n, n-1, n-2-1, 0 segment positions apart, when n is the minimum difference in segment position permitting the fastest sequential actuation of any two type bars, means responsive to entry of coded signals into said fixed register means for generating discrete signals representing the difference in segment position of the last and next to be actuated type bars whose coded signals are in said fixed and counting register means including, a pulse generator operable on entry of signals intO said fixed register means to pulse said counting register, means comparing the coded signals in said fixed register means and the coded signals in said counting register for coincidence and for generating a coincidence signal, means for counting to 2n in response to pulses from said pulse generator, and means for generating discrete signals corresponding to the count in said counting means if coincidence occurs within 2n counts, means for passing said discrete signals to trigger corresponding one shot multivibrators for generating output signals whose duration establishes the interval of delay necessary after energization of the last print solenoid as will allow energization of the print solenoid associated with the type bar whose coded signals were entered into said fixed register means in the soonest possible time, and gating means controlled by output signals generated for clearing said counting register, for transferring coded signals from said fixed to said counting register and for energizing the print solenoid associated with the type bar represented by the coded signals transferred to said counting register. 